List all C Expressions from old MDL

I'm developing new addins to a system (+20 years old) and I need to handle with some old MDL which I don't have the code. This system also interact with Oracle and others systems, so I'm not even thinking to redo the entire system. I also don't have access to the developer (and the source code).

I do not need to change the original code, just send and receive data from it. From some VBA codes I can identify some C expressions, which is used in Get/SetCExpressionValue, but I don't have all of them. 

Is there a way to list all C Expressions avalible for some MDL application?